Change your SSH server port to reduce brute force attacks

Reduce SSH brute force attacks by changing your default SSH server (sshd) port from port 22 to a different one. Below is a sshd log example of a brute force attacks.

Changing the port

You can change the default port by editing the sshd configuration file.

sudo nano /etc/ssh/sshd_config

Find the line that say #Port. Remove the # symbol and set the port number you prefer. Refer to the image below as reference.

Logging In

After changing the SSH port, you can now login using the following commands:

ssh

ssh -p 34092 [email protected]

scp

Transfer files using scp with capital -P as parameter

scp -P 34092 file.txt [email protected]:file.txt

rsync

Push

rsync -azvP -e 'ssh -p 34092' SOURCE [email protected]:DEST

Pull

rsync -azvP -e 'ssh -p 34092' [email protected]:SOURCE DEST

Conclusion

This is just one way to reduce brute force attacks. You can further harden your server by using a firewall that only allows connections from specific IP or IP ranges. You can also use Fail2Ban, a software that automatically blocks users who already reached the invalid attempt count.